Diagnostic Strategies in the Hypothesis-Directed PATHFINDER System

PATHFINDER is a developing expert system to assist pathologists in the interpretation of findings noted on microscopic examination of lymph node tissue. We describe PATHFINDER’s hypothesis-directed reasoning approach with an emphasis on intelligent question selection strategies, techniques for managing data inaccuracy, and explanation methods for justifying questions asked of the pathologist. Although this work was originally inspired by the INTERNIST-1 approach in building an expert system for pathology.